Blank for gears and method of making the same



- E. J. GUAY BLANK FOR GEARS AND METHOD OF MAKING THE SAME Filed May 10, 1923 I 2 Sheets-Sheet 1 9' T2 71. 5 I Fig.2. 2 19.5.

- nvenidr: Emile J Guaey IIIHII' I I13 itforney.

July '8 1924. 3,501,027

E. J. GUAY BLANK FOR GEARS AND METHOD OF MAKING THE SAME Filed May 1o 1923 2 Sheets-Sheet 2 fare): for Zmz'l J; Gaay Patented July 8 1924.

STATES I 1,501,027 PATENT OFFICE.

EMILE J. GUAY, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC GOM- PANY, A CORPORATION OF NEW YORK.

BLANK FOR GEARS AND METHOD OF MAKING THE SAME.

Application filed May 10,

To all whom it may concern:

Be it known that I, EMILE J. GUAY, a citizen of the United States, residing at Lynn, county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Blanks for Gears and Methods of Making the Same, of which the following is a specification.

' The present invention relates to gea which are composed of woven textile material such as canvas or duck arranged in layers, said layers being united by a binder such for example, as a Iphenolic lcondensation product and which a so retains the fibres of the material under compression. In a gear blank of this character the material represents the principal cost of the finished product, and as heretofore constructed there has been substantial wastage due to the trimmings or pieces which remain after the disks or blanks are cut from sheets.

Gears of this type are very-largely used in the timing gear trains of automobiles and when so used are provided with spiral teeth for the purpose of improving the smoothness of action. Such gears are at times subjected to very heavy stresses due to torsional strains on the crank shaft and also to irregularities in the firing of the cylinders of the engines.

My invention has for its object to improve the construction of gears and gear blanks of the character described and also the method of making the same to the end that the finished gear will be capable of withstanding the heavy stresses to which it is subjected and that the material used in the manufacture will be economically utilized.

For a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and the claims appended thereto.

In the accompanying drawings, Fig. 1 is a plan view of a sheet of canvas or duck which has been treated with a phenolic condensation product showing how the same is cut to form parts of the gear blanks; Fig. 2 is a plan view of a disk; Fig. 3 is a plan view of a rim washer; Fig. 4 is a plan view of an inset or end disk; Fig. 5 is a sectional view of the same; Fig. 6 shows the sectors which are cut from the center part of a rim washer; Fig. 7 is a plan view of a complete sector; Fig. 8 is a plan view of one of the marginal pieces remaining after two disks 1923. Serial No. 638,087.

are cut; Fig. 9 is a plan view of a starshaped piece remaining after four disks are cut; Fig. 10 is a plan view of a segmental piece cut from the stock between four disks; Figs. 11 and 12 are respectively a plan and sectional view of a fixture in which the parts are assembled to form a blank; Fig. 13 is a side view of a gear artially in section; Fig. 14 is a slight modi cation of the way washers and sectors are cut, and Fig. 15 is an exploded view showing the eneral arrangement of thevparts of a comp eted gear blank.

In the manufacture of gears and blanks therefor, the canvas or duck is first coated on one or both sides with a phenolic condensation product, such as bakelite or other equivalent binder. This coating is usually done by passing the canvas or duck through a tank containing the binder, after which it material with the binder which action tends Y to make them brittle. In other words, the vacuum treatment removes the binder from the center of the hard, twisted threads and hence when the final ressure is applied the binder will bond the i'ibers together withoutdestroying their flexibility, which is of greatest importance because it has a direct bearing on the strength and life of the finished gear.

I will now describe the manufacture of a gear blank of a predetermined size from a sheet of canvas 0r duck of a predetermined size but it is to be understood that this is given merely as an illustration and not as a limitation of my invention. The example given will however, indicate very clearly how economically and to the best advanta e a piece of material can be utilized. It W1 1 of course be evident that odd pieces of material can be employed in addition if necessary or desirable.

Referring to Fig. 1, 15 indicates a square sheet of woven material such as canvas or duck which has been previously-coated with a binder such as bakelite. From this sheet are cut twenty-five disks 16 of the size indicated. There remains along this marginal edge of the sheet as trimmings, sixteen pieces 17 each having three points. There also remains as trimmings between the disks star-shaped pieces 18, each. having 'four points, of which eight are utilized as such. The other star-shaped pieces are cut to form eight segments 19. The parts 17 and 18 are cut away in the center to receive the small rlirietallic hub of the gear blank as shown in It will be observed that the star-shaped pieces whether made of one piece or two, have four points and when assembled these points register with the converging spaces between the sectors and segments which are made from the trimmings that remain after the washers are cut. As a result of the cutting operations above outlined, there re mains a very small amount of trimmings, i. e., the corner pieces 20, that cut out of parts 17 and 18 and the end disks and the small pieces from around the segments 19. These irregularly shaped pieces of trimming are chopped up into relatively small pieces and are used wholly or in large part in forming the thickened hub of the blank as will appear later on.

Two of the disks 16 are employed as end or finishing disks each of which has a preformed inset as indicated at 21 in Fig. 5. The pre-forming is done when the disk is soft and pliable by means of a form or fixture having a spring follower which holds a peripheral portion of the disk to prevent wrinkling while the inset is formed to shape. The remaining twenty-three disks are cut to form rim washers 22 as shown in Fig. 3. The center piece 23 from each washer is cut into three sectors having an arc of 120 each. As these sectors are later employed as parts of the rim it is necessary to change the radius of curvature to conform to that of the washers. To do this a die is employed by means of which the three parts are cut as shown by the dotted lines in Fig. 6. Fig. 7 shows one of the complete sectors 24. The peripheral surface 25 has the same radius of curvature as the outer surface of the washers and the distance between the point 26 and the periphery is equal to the distance between the metallic hub of the blank and the periphery of the disk. It is also equal to the distance between the hub and the inner wall of the fixture used in theassembling operation. The sides of the sector are cut away for a short distance as indicated at 27. The washers and sectors may be cut by a single die operation or by a succession of such operations.

From Fig. 11 it will also be seen that when assembled the sides of the sectors lie in planes which are tangential to the periphery of the metallic hub, or substantially so. As will appear more fully later on these sectors are angularly advanced layer by layer so that the tapered ends of the sectors in one layer register with the spaces in adjacent disk or a removable piece having that shape may be employed. In the fixture are stacked or laid up the various separately-formed parts previously described. After all of the parts are assembled, a head 30 having an under side which conforms to the shape of the top insert disk is placed on top, after which the material is subjected to pressure to compress the fibers of which the woven material is composed and to heat to cure the binder or cause it to set and retain the fibers in their compressed state or condition.

In the bottom of the fixture is placed the metallic hub 31, Fi 12, which has a flange at the lower end an o a knurled surface 32 to ensure good bonding with the textile material.

In assembling the blank the hub 31 is held in position by a stud 33, the lower end of which makes a snug fit with the walls of an opening in the bottom of the fixture. The stud is provided with a shoulder that is seated on the top of the hub and holds it from moving upwardly. The diameter of the upper part of the stud corresponds to the diameter of the hub so as to facilitate slipping the various parts into position around the hub. As wil appear later on, certain of the parts are assembled around the hub and extend outwardly and other parts are assembled adjacent the inner wall of the fixture, engage the same and extend inwardly to the hub. The outwardly and inwardly extending parts are arranged to overlap and hence to interlock.

In assembling the blank a pre-formed disk 21 is first placed in the bottom of the fixture, after which three rim washers 22 are inserted with their peripheral edges engaging the inner wall of the fixture. One of the four pointed star-shaped pieces 18 is then slipped over the hub as best shown in Fig. 15. Because the hub is relatively long measured axially, a certain amount of filling material in the form of small pieces 34 is next inserted in place around the hub. These pieces are formed by chopping up the trimmings which remain after the principal parts are die cut from the sheet material. The next step is to lay four of the sectors 24 in place withtheir apices 26 engaging the hub and their peripheral surfaces engaging the inner wall of the fixture.

As the circumference of these pieces when laid in place is somewhat greater than a complete circle, there is at one point an overlap of two adjacent pieces as best shown at 35 in Figs. 11 and 15. Of course, each sector could be arranged to slightly overlap the adjacent sector but as this would require more care in the assembling operation, I prefer to have the overla at one point only. On top of the sector is placed a rim washer 22. One of the star-shaped pieces 18 is then placed in po'sitionon the hub and its points are advanced angularly with respect to the previously inserted starshaped piece. This advance is the same or substantially the same as the amount of the overlap indicated at 35. As the parts are built up one layer after the other this overlapping and advancing arrangement is followed so that the material will be distributed as uniformly as possible to the end that when the final pressure is applied the density of the material at all points will be as nearly uniform as possible which would not be the case if the same parts exactly registered at all points. To state the matter in another way, the joints between the sectors in the complete assembly form a spiral beginning at the bottom and ending at or near the top, the last joint being approximately axially aligned with the first. That'is to say, the spiral formed by the joints is approximately 360 and progresses from one side of the blank to the other.

The next step is to insert four sectors 24 the right hand edge of the first one inserted being lined up with the left hand edge of the sector in the layer below. On top of this is placed a rim washer 22, then a starshaped piece 18 is placed on the hub, the points of the star being advanced over the points of the preceding star, the various parts bein aligned as shown in Fig. 11. From this figure it will be seen that the starshaped pieces have their points located between the cut away portions 27 of the sectors, and because the sectors are angularly advanced layer by layer, it follows that the star-shaped pieces must also advance layer by layer and by the same amount. In Fig. 11 the horizontal section is such that it 18 just above a star-shaped member composed of two pieces 17 but the arrangement is the same whether made of one piece or two. This method'of assembling four sectors, one rim Washer and a star is repeated until about one-half of the blank is assembled when all of the star-shaped pieces 18 which were cut from the blank are used up, after which the same plan is followed but using the parts 17 of which there are sixteen or a total of ei ht complete stars.

As previously stated, there are eight segments 19 and these are placed between the other parts in the same manner'as the sectors 24 except that the arc" covered by each segment is less than the are covered by each sector and hence the overlapping feature is absent where these are used. It will be observed from Fig. 15 that when the segments are inserted in their proper relation that four radial spaces 19 are left which register with the pointed ends of the four pointed star in an adjacent layer said spaces interspersed with layers of sectors 24. The U general plan of procedure is followed until all of the various parts out from the sheet are used up. Just before the pre-formed, end or finishingdisk is applied, I may, if

desired, add some of the chopped-up pieces 34 to help fill up the hub portion. The last step in the assembly is to insert a preformed or end disk and then apply the head 30. I have referred to different layers made of sectors 24 and others made of segments 19. It is evident that the layers made of segments (which are less in number than those made of sectors) may be located at any suitable part of the blank, and the same is .true of the four pointed star pieces, some of which are made of one piece and some of ,two. The main consideration is to properly intersperse the elements in such manner that they will be uniformly distributed, will interlock one layer with the next and have approximately the same unit density at every point.

After the parts have been assembled in the fixture the latter and its contents are placed in an oven and given a preliminary eating so as to soften the material and thus avoid distortion or breaking of the fibers of the canvas or duck in the pressing operation. After the preliminary heat ng the fixture and its contents are ut into a hydraulic press, the latens of w ich can be heated by steam an later cooled by water. A ring-or follower, shown in dotted lines, Fig. 12 is placed on top of the head so as to permit of the pressing operation without interference from the stud or wall of the fixture. It is preferable to apply pressure to the blank rather slowly at. the start in order to give the air a chance to escape from between the layers of material after which the final desired pressure is applied. After the heating and pressing operation, the steam is shut off and water is admitted to the platens to cool the fixture and its contents. During these operations the binder is cured or set and serves to hold the fibers under the heavy compression to which they have been subjected. The blanks after being removed from the fixtures are placed in an oven and subjectedto a moderate temperature for a number of hours, during which time the curing process continues to some extent accom anied by a small shrinkage.

When a b ank thus formed is removed from the fixture its surfaces will be found to present a smooth, glass-like appearance and are highly polished, thereby avoiding the necessity of further finishin The end disks in addition to finishin t e sides of the blank also serve to tie t e rim to the hub, thereb increasing the strength of the blank as a w ole.

After the blank is formed the periphery is turned to the exact diameterrequired, and the teeth 37 cut thereon as shown in Fig. 13.

In Fig.'6 is shown one way for cutting the sectors from the center pieces of the washers. As the radius of curvature of the sectors has to be changed in order to make the outer surface conform to the radius of curvature of the washer there is some waste represented by the material between the dotted line 36 and the boundary line. In Fig. 14 is shown an arrangement whereby even this small waste can be eliminated. This is done by cutting the center art of the washer as shownby the dotted hnes 38, so that the sectors are cut to their final form by one operation. This results of course in modifying the inner surface of the rim washer from a true circle but by advancing the angular position of-the washer in successive layers by a certain amount that portion of the washer having thesmallest radial dimension will be covered by that portion of another washer having a greater or the greatest radial dimension as desired. In other words, in the preferred arrangement the washers will be advanced one with respect to the other by 120.

It will be noted that one of the characterized features of the blanks is that certain members or elements are built up around the hub and extend outwardly while certain other members or elements are built up to form the rim and extend inwardly, portions of the said members or elements of the two parts overlapping in such manner as to interlock in the finished blank.

It will be seen from the foregoing that the underlying feature of my invention is that of cutting the rimwashers from a sheet of textile material using the trimmings remaining after the washers are cut and the washers to build up the hub, web and rim, and holding the parts so cut and arranged under compression b a suitable means.

It is possible to o away with the preformed end disks but it is referable to use them because they give a etter finish and appearance to the finished blank, and they also add strength to the blank. When they are omitted the top and bottom layers are formed of sectors 24 or segments 19, the rim'washers' 22 and star-shaped pieces being located between them.

It is evident from a study of the subject that the only part of the gear blank in which material can be saved is in the web because the widths of the rim and hub are .pretty definitely fixed by the load which is to be transmitted by the gear. By carefully selecting and shaping the pieces which form the hub and web and assembling them in interlocking arrangement as described, I am able to make a very substantial saving in the cost of the blank without however sacrificin U the strength thereof. The decrease of stock in the web is due, of course, to the spaces which are left between the sectors and segments when assembled in place by layers and also to the inwardly-curved sides of the star-shaped pieces. It will be seen, however, particularly from Figs. 11 and 15, that there is ample overlap of the pieces to ensure proper anchorage of one part to the other. The fact that the web is thinner than the hub and rim has the advantage where the teeth are spirally cut in that the web can yield laterally by a slight amount when subjected to hea shocks which. otherwise would have to e absorbed directly by the teeth. To avoid the concentration of undue stresses in the web sharp corners should be 1. The method of making blanks of the character described, which comprises cutting definitely shaped members from sheet textile material, building up the blank from the members and the trimmings which remain after the members are out, said members being interlocked with the trimmings, and finally subjecting the material to compression and retaining it in that condition.

2. The method of making blanks of the character described, which comprises cutting rim members of the desired radius of curvature, building up the blank with trimmings which remain after thBtIDEIl'lbBIS are cut, certain of the trimmings being interspersed with the members to form the rim and certain other of the trimmings being positioned within the members and interlooking with the-first to form a support for the rim, and subjecting the material to compression and retaining it in that condition.

3. The method of making blanks of the character described, which comprises cutting rim members from sheet textile material,

building up the blank from the members and the trimmings which remain after the members are cut, the trimmings from the inside of the members being positioned to cooperate with the members to form the rim and the trimmings from the outside of the members being positioned within the members and cooperating with the others to form a support for the rim, and finally subjecting the material to compression and retaining it in that condition.

4. The method of making blanks of thecharacter described, which comprises cutting washers from' sheet textile material, building up the blank from the members and the trimmings which remain after the washers are cut with said washer and trimmings in interlocked arrangement, and finally subjecting the material to compression and retaining it in that-condition.

5. The method of making blanks of the character described, comprising cutting rim members from sheet textile material, assembling said members about a metallic hub, building up the body of the blank from trimmingswhich remain after the members are cut, certain of said trimmings bein interspersed with the members and exten ing inwardly toward the hub, certain other trimmings being mounted on the hub and extending outwardly, said trimmings interlocking to form the web, and finally subjecting the material to compression and retaining it in that condition.

6. The method of making blanks of the character described which comprises cutting rim washers from sheet textile material, assembling said washers about a metallic hub, cutting the trimmings from inside of washers into sectors and placing them between the washers to form a thickened rim, there being outwardly converging spaces between the sectors, mounting the outside trimmings of the washers on the metallic hub and in approximate register with said spaces, and finally subjecting the material to compression and retaining it in that condition.

" 7. The method of making blanks of the character described which comprises cutting rim washers from sheet textile material, building up the blank layer by layer with washers and pieces cut from the inside of the washers and other pieces cut from the outside of the washers, said layers being arranged in interlocking arrangement with each other and with the washers, and finally subjecting the material to compression and retaining it in that condition.

8. The method of making blanks'of the character described which comprises cutting rim washers from sheet textile material, building up the blank layer by layer with pieces cut from the inside of the washers and other pieces cut from the outside of the washers, said inside pieces being interspersed with the washers to form the rim, said outside pieces interlocking with the first-named pieces to form the-web, and finally subjecting the material to compression and retaining it in that condition.

finally subjecting the material to compres sion and retaining it in that condition.

10. The method of making blanks of the character described which comprises cutting disks from a sheet of textile material, form ing insets in certain of the disks to form the sides of the blank, cutting rim washers from the remaining disks, cutting the trimmings from within the washers into sembling the washers in interlocking relation with the pieces, assembling the outside trimmings within the washers andrin interlocking relation with the pieces to form a support for the rim, and finally subjecting the material to compression and retaining it in that condition. y 11. The method of making blanks of the character described which comprises cuttin disks from a sheet of textile material in suc manner that trimmings in the form of pointed pieces remain after the cutting operation, cutting out the centers of the disks to form sectors, cutting certain of the pointed pieces to form segments, assembling the sectors and segments by layers in interlocking arrangement with the washers, there being spaces between adjacent sectors and segments in each layer, assembling the pointed pieces by layers inside of the washers with their points approximately registering with said spaces and their base portions overlaping some portion of the sectors and segments, and subjecting the material'to cpmpression and retaining it in that condition.

12. Themethod of making blanks of the character described which comprises cuttin rim washers from a sheet of textile materia cutting the centers of said washers to form sectors, assemblin the washers, segments and outside trimmings left after cutting the pieces, as;

washers to form a supporting body for the l rim, said sectors in each layer having an overlapping joint, the joints in successive layers being angularly advanced, the layers of sectors being interspersed with the rim washers, inserting said outside trim in the center of the body and in interlo g 13. The method of making parts for a blank of the character described which comprises cutting disks from a sheet of textile material, cutting out the centers of the disks to form washers, and cutting said centers to form sectors, the radius of curvature of each sector corresponding to that of the washers.

14. In a blank of the character described, the combination of the rim washers which are cut from sheet textile material, a body portion comprising sector-shaped pieces and star-shaped pieces, said sectors and washers being interspersed to form the rim and the sectors and star-shaped pieces being interspersed to form the hub and web, and means for retaining the fibres of the material in a compressed state.

15. In a blank of the character described, the combination of a metallic hub, rim-forming sectors arranged in layers, each of which engages the hub at its inner end, said sectors having outwardl converging spaces between them, star-s aped pieces which engage the hub, the points of which register with said converging spaces, means co-operating with the sectors near their peripheries to increase the thickness of the rim, and means for retaining the fibers of the material which surround the hub under compression.

16. In a textile material blank of the character described, the combination of rim washers, rim-forming sectors in layers with outwardly-converging spaces between the sectors of eachlayer, central pieces also arran ed in layers which have outwardly exten ing tapered portions which register with said spaces and a portion interlocking with the sectors, and means for retaining the fibers of the material in a compressed state.

17. In a blank of the character described, the combination of rim-washers, a metallic hub, sectors arranged in layers and inte1-- spersed with the washers to form the rim the sides of the sectors lying in planes which are substantiallytangentially to the periphery of the hub, and the tapered ends of the sectors in one layer overlapping the spaces between such ends of another 1ayer,

said washers and sectors being made of textile material, and means for retaining said material in a compressed state.

18. In a blank of the character described, the combination of rim washers, a metallic hub, sectors arranged in layers and interspersed with the washers to form the rim, segments also arranged in layers and interspersed with the washers, said sectors and segments having outwardly-converging spaces between them, star-shaped pieces which engage the hub, and are interspersed with the sectors and segments, the points of the starshaped pieces registering with and partly covering said spaces in the successive layers, and means for retaining the fibers of the textile material of which the sectors, segments and star-shaped pieces are held in compresslon.

19. As an article of manufacture, a blank for gears comprising sectors of textile material arranged in layers, the sides of each sector being cut away to form an enlarged space, the pointed ends of the sectors in one layer partially overlapping the said spaces in another layer, hub members also made of textile material each having projections which partly cover the spaces in certain of the layers, a metallic hub which is enclosed by the members, and a binder for uniting the parts of the blank and holding the fibers in compression.

20. As an article of manufacture, a textile material blank for gears having a relatively thick rim and hub and a relatively thin connecting web, inset disks which form the sides of the blank, interspersed washers and sectors between the disks, the sectors ing the fibres of the textile material underv compression.

21. A gear blank made from a sheet of textile material, comprising rim washers, sectors which are interspersed with the washers and are arranged in layers, certain of the sectors in each layer having overlapping ends, said overlap progressively advancing layer by layer, a metallic hub, starshaped pieces which engage the hub and are interspersed with the sectors to form the web, and a means for holding the textile material under compression.

22. An element for a blank of the character described, comprising a sector having a peripheral edge, the radius of which is equal to that of the blank in which the element is to be used and two converging sides which have cut-away portions, the distance between the apex and said edge being less than said radius.

In witness whereof, I have hereunto set my hand this 7th day of May, 1923.

' EMILE J. GU Y. 

